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Astronomy Week 6-9 Quiz.docx

An emission line spectrum of a hot gas d a flat

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An emission-line spectrum of a hot gas d. A flat spectrum with absorption lines e. A blackbody spectrum with absorption lines Answer: E 7. The Hertzsprung-Russell Diagram is a plot of ____ versus ____ for stars a. Mass, luminosity b. Distance, apparent brightness c. Color, radius d. Mass, radius e. Luminosity, temperature Answer: E 8. How do we know that nuclear fusion in the core is actually providing the Sun’s  energy?
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a. We observe that the Sun is not shrinking in size  b. We don’t have any direct evidence of nuclear fusion, it is just a hypothesis c. We measure an increase in the amount of helium at the surface of the Sun d. We observe neutrinos created by the proton-proton nuclear fusion reaction e. We find earth rocks more than 30 million years old Answer: D 9. A consequence of hydrostatic equilibrium is that stars will have a. Hot, dense, compact cores surrounded by cooler, lower-density envelopes  b. A strong mass-radius relationship c. A strong mass-luminosity relationship d. Nuclear fusion cores surrounded by convective envelopes Answer: A 10. A star is said to be in Hydrostatic Equilibrium if a. Its luminosity depends on its mass b. It is expanding slowly due to gas pressure c. It is contractly slowly under gravity  d. Its internal pressure and gravity are in balance  Answer: D 11. A star in hydrostatic equilibrium with no source of chemical or nuclear energy will a. Still shine by releasing gravitational binding energy (Kelvin-Helmholz Mechanism) b. Steady evaporate into the vacuum of space c. Explode as a supernova d. Immediately go dark e. Cool off and fade away Answer: A 12. The stellar spectral classification sequence OBAFGKM developed by Annie Jump  Cannon is a sequence of stellar _____
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a. Temperature  b. Chemical composition c. Mass d. Radius e. Luminosity  Answer: A 13. A star in hydrostatic equilibrium undergoes a slight increase in internal pressure. In response, the star will a. Explode as a supernova b. Not change in radius c. Collapse to form a black hole d. Expand in radius e. Get smaller in radius Answer: D 14. What are the primary physical parameters that characterize stars? a. Apparent brightness, distances, mass, and radius b. Distance, luminosity, color, and chemical composition c. Mass, radius, luminosity, and temperature d. Mass, luminosity, distance, and color e. Mass, radius, temperature, and chemical composition Answer: C 15. Most of the stars nearby the Sun are found where on an H-R diagram?
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  • Fall '18
  • hydrostatic equilibrium

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